Furnace



Jan. 1, 1935. E G, BA|LEY` 1,986,662

' FURNACE Original FiledMarch 17, 1928 5 Sheets-Sheet l ATTORN EYS 3Sheets-Sheet 2 INvr-:NToR

ATTORNEYS A E. G. BAILEY FURNACE Original Fi led March 1'7, 1928 Jan. 1,1935.

Jan. l, 1935. E. G. BAILEY 1,986,662

i FURNACE Original Filed March 17.11928 3` Sheets-Sheet 3 INVENTORErl/in G.' Bailey BDERXM ATTORNEY pulverized coal, which in burningforms slag,`

Patented Jan. l, 1935 UNITED STATES PATENT OFFICE' FUBNACE Ervin G.Bailey, Easton, Pa., assignor to Fuller Lehigh Company, Fullerton, Pa.,a corporation of .Delaware Application March 167,

1928, Serial No. 262,363

Renewed October 7, 1932 22 Claims.

trouble has been experienced in disposing of the slag which isdepositedvin the bottom of the furnace directly from the burning fuel,or else gathers on the walls of the furnace and runs down onto thefloor.

The accumulation of slag on the floor is added to by chunks`of slagwhich may collect in the furnace above the floor and then drop down whenthey become loosened from the'tubes. The slag on the floor, when itbecomes cool, fornis a solid mass of extremely refractory material whichis difficult to remove, and it is to the removal of such slag that m`yinvention ls directed.

f In the accompanying drawings, in which I have shown a selectedembodiment of the invention:- Fig. 1 is av vertical sectional viewthrough the lower part of a furnace, constructed according to myinvention. i

Fig. 2 is a fragmentary section line 2'2-2 -of Fig. 1.

Fig.- 3 is a fragmentary elevation on an enlarged scale, and showing theinterior of the furnace wall at the slag tapping opening.

Fig. 4 Vis a sectional view through the slag tapping opening, beingtaken on theV lines 4-4' of Figs. 2 and 3.

Fig. 5is a fragmentary elevation ofthe outer taken on the face of thefurnace'wall at the slag tapping and access openings, and taken on theline 5--5 of Fig. 2.

Fig. 6 is a section on the line 6-6 of Fig. 4.

Fig. 7 is a sectional elevation illustrating the furnace shown in Figs.1-6 as incorporated in a steam generator or boiler;

For the purposes of illustration, I have shown my invention 4as appliedto `a furnace having substantially vertical walls, of whch` are shownthree, 1, 2 and 3, each of which is formed by vertically extendingwaterI tubes 4, 5 and 6, re-

spectively, connected at their lower ends to headers 7, 8 and 9 to whichan appropriate covering may be applied. 'I'he upper ends ofthe water itubes are connected vto theusual -upper headers (see Fig. '7) Normallywater is admitted to the lower header rising through the tubes in thewall' where some steam will be formed. Steam and water are dischargedfrom the upper header. Such furnace walls would normally form part of asteam boiler and as such are ltermed water walls.

AIt will be noted that` each of the lower headers,

is independent of the others, whereby eachwall may expand and contractin a vertical direction independently of the others, and the lowerheaders are preferably carried on spring supports 10. The covering forthe wall tubes may comprise individual tile or blocks 11, which are bestshown in Figs. 4 and 6, these blocks being formed with refractory faces12 and metallic backings 13 which are in close engagement with thetubes, where 'they are held by suitable clamps 14. The details of theblocks and clamping means have been omitted from Fig. 2,'forv the sakeof clearness. andbecause of the small scale' of this figure.

The floor of the furnace is supported upon suitable beams 15 andsometimes-comprises a single course of brick 16, although in theillustrated embodiment two courses are shown. Upon this course ispreferably placed a layer of dolomite 17, and the course of brick ispreferably laid loosely on the supporting plates 18 disposed on thebeams15.

Adjacent the edges of the floor, the plates 18 upon which the brick workis supported, extend substantially into `contact with the side walls, asbest shown in Fig. 4. The brick work course 16 is provided withexpansion joints 19, which are covered by a plurality of courses 20extending along the walls.

In one or more of the side walls is disposed a burner indicatedgenerally at 21, and which is preferably adapted to burn pulverizedcoal. The

burner should preferably be one which will give great turbulence to theincoming fuel, and it will be noted that the burner is so arranged as toproject a flame horizontally and relatively close to the floor. 4

Y In the embodiment shown, I contemplate placing a burner in each wallsubstantially in the posi- Jtion shownfso that the flamestherefrom willintersect within the furnace and in such a. way as to cause stillgreater turbulence than is present in the individual streamsof fuel,thus providing thorough'mixture of the air and fuel, and comi pletecombustion of the fuel.

The burning fuel will form slag, as is wen known imity of the streams ofburning fuel which, as,

noted above, are relatively close to the floor, and therefore maintainthe temperature of the slag on the floor sufllciently high, to keep itin its molten state.

`The slag is preferably tapped through a suitable opening in one of thefluid cooled walls indicated at 22, from which .it runs down a spout 23associated with the opening 22. This spout is preferably formed of twosections, as best shown in Fig. 4, one section being supported betweenears 24 and the other being pivoted at 25 upon these ears 24, and beingprovided with an apron 26 which, when the outer section 23' is lifted,will close the end of the inner section of the spout.

Tapping of slag is intermittent, and between tapping periods the levelof the slag pool rises, thereby completely submerging the floor andwhatever may be upon it. By the rising and falling of the slag level thecontents may be thoroughly mixed in a molten condition through a processof liquid diffusion.

The tapped slag may be permitted to run into a sluiceway, where it maybe subjected to jets of water which will break it up and carry it away,or it may be tapped directly into a stream of running water. Again, itmay be run on to the floor and quenched, or may be handled in any'othersuitable way. The slag at the opening 22 forms a crust of chilled slagwhich may be easily broken by a bar, in order to permit the flow ofslag, and then the slag may be permitted to run until the crust formsagain and there is insufcient pressure behind it to break it, or ifdesired, the hole may be plugged, to stop the ow of slag before thecrust would form by itself. In this connection, it should be noted thatthe spout forms a convenient guide and rest for a bar used in working atthe tap hole.

Adjacent the tap hole, I preferably provide an access door indicated at27. Normally, this door is bricked up as shown in Figs. 1 and 2, thebrick being removed when it is desired to enter the furnace through thedoor.

Disposed in front of the two openings formed by the door and the taphole, and spaced from the wall of the furnace, is a transverselyextending header box 28. 'Ihis box preferably extends beyond bothopenings and is connected to the wall tubes above these openings, thesetubes being bent outwardly as best shown in Fig. 4, and expanded.

into the box.

Disposed beneath the door 27 is a second transversely extending headerbox 29, connected by nipples 30 to the header 8. The boxes 28 and 29 areconnected by nipples 31 disposed on opposite sides of the door 27.Disposed on opposite sides of the tap hole are two nipples 32, whichconnect the header 8 to the box 28. By the above arrangement, aconvenient disposition of the access door is provided, and propercirculation of water past both the access door and'tap hole is alsoobtained. At the same time, the tubes are disposed far enough from thetap hole to prevent their chilling the slag and thus preventing orhindering its ow.

Air may be introduced -beneath thev iioor through the conduit 33, to aidin maintaining the floor and the supporting steel work relatively cool.

In operation, the furnace is started and as the slag accumulates on thefloor, it is maintained in a molten condition by the intense heat of thefire which is relatively close to the floor. It will be noted that thedolomite covering forming part of the floor is extended upwardly towardthe walls, as best shown in Fig. 1, this material being installed loose.

As the slag accumulates and reaches a point above the tap hole, it maybe tapped off if found desirable.' If it is vintended to use the slagfor manufacturing purposes, as an ingredient in a composition of matterfor which it may be suitable, any desirable material may be added to thepool of slag before tapping. For example, limestone or feldspar .aresubstances which may be -to cause such slag to solidify in the openings.

Lacasse added, although of course I do not intend to limit myself tothose substances alone. rial may be introduced through the usualobservation doors, not shown.

As the molten slag accumulates, a pressure is exerted laterally againstthe walls of the furnace, and this pressure may be taken up by thesliding expansion joint between the oor and the walls. Similarly, theheat from the burning fuel may cause expansion of the walls, and thisaction may take `place against the opposition of the resilient supports10. It will be observed that the spout 23 is adapted to move'with thewall upon expansion or contraction of the wall, as just described.

The heat from the pool of molten slag will aid materially in maintaininga high furnace temperature, and the heat is partly carried to the walltubes by means of the heat conducting tile supported on the tubes, thetubes maintaining the walls cool, so that the high temperature generatedby the burning fuel and the pool of slag does not destroy them. Thewalls are preferably made of the heat conducting tile indicated in Fig.4,` except at the two openings where a magnesite or other suitable brickmay be employed instead of the tile. Such brick are easily replaceablewhen burned.I out. By this means, a high furnace temperature may bemaintained Without damage to the walls, the heat passing through thetile which are of high conductivity, and thence into the water or othermedium circulating in the tubes in the walls. Thus, the walls are notonly maintained in the presence of a high furnace temperature, but theheat is put to a useful purpose. At the same time, ample provision ismade for expansion and contraction of the walls.

It will be noted that the refractory and metal parts of the furnacebottom are arranged to insure that there will be no leaks of slagtherethrough. By a leak, I mean a slag iiow at a place other than thatat which the slag is intentionally permitted to flow from the furnace,at which place, of course, Aproper provision will be made against damagefrom such ow. If such a leak were permitted, the stream of liquid slagowing through such a leak, would soon cut the refractory and even themetal parts, by dissolving and eroding the materials along which theslag iiows. This is not true, however, of casual openings extending only-partially through the oor. The heat from the slag which would ilow intosuch openings may be conducted away with the floor coolingprovisionsdescribed fast-enough In other words, a continuous flow of slag willcut, whereas quiescent slag has little or no effect in this respect.

Similarly, the flow of -uid slag down the side walls of the furnacewould soon cut these walls,v

were it not for the cooling of these walls by the tubes, which keeps thewall surfaces below the temperature necessary to cause the materialsthereof to enter into solution in the slag. This is aided by any layerof solidified or semi-solidified slag which may adhere to such surfaces.

'In the construction described, the-slag from the side walls flows outon the furnace oor, where it joins the slag deposited directly on theoor from the combustion space to form a fluid mass. The joint betweenthe sides of the floor and the side walls is kept tight enough to insurethat the slag will not leak through at this point. the angle ironconnected to the lower part of each wall, on which plate 18 rests,forming an effective seal for this purpose. By carrying the water tubeswell below the top of the floor, protection of all parts of the wallwhich may be contacted with fluid slag is insured.

The maintenance of the furnace floor' in a relatively cool condition bysupplying cooling air in contact therewith cools the lower layer of slagon the floor and renders that portion ofthe slag when the furnace isused in connection with a boiler, there may be lay-over periods duringwhich the combustion rate may be so low that there will not be asuilioientlyhigh furnace'temperature to maintain the slag on the floormolten. As soon as the combustion rate is increased, however, to put theboilerinto full operation, the increased temperature of the furnace willfirst put the upper part of the accumulated slag into a condition inwhich it may flow from the furnace. Therefore, when I Adescribe the slagas being maintained in a molten condition, I do vnot intend that it'mustbe in such condition at all times, but only at such times as the furnaceis in normal operation.

Moreover, it is to be understood that, even when the slag is flowingthrough the tap hole 22 or other outlet opening, there is a pool of slagmaintained, even if such opening is never closed, because 'the moltenslag flowing over-the floor will keep a layer of molten slag on thefloor to prevent any-hardened layer on the top of the iloor frommelting, which would permit the floor to be "cu by the owing slag. Wherethe slag is tapped intermittently, as in my preferred form, thisprotection is insured by locating the bottom of the said chamber havinga substantially horizontal slag receiving floor and side walls held incontact with the sides of the floor and arranged to prevent slag leakingtherebetween, and vertical water tubes in said side walls and extendingbelow the top of said floor, the faces of said side walls being formedof heat conducting blocks attached to and i in close thermal contactwithsaid tubes, some of said blocks contacting with the sides of saidfloor,

s aid chamber having an opening through which molten slag may flow andsaid burner being constructed to impart suilicient heat to slag on saidfloor vto maintain at least its surfacev in a fluid condition. a

3. In a furnace, a combustion chamber, a burner to burn a slag-formingfuel in said chamber,

said chamber having a substantially horizontal slag receiving floor andside walls held in contact with the sides of the iloor'and arranged tovprevent slag leaking therebetween, and vertical water tubes in said sidewalls and extending below the top of said floor, said chamber having anopening through which molten slag may flow and said burner beingconstructed to impart su'flicient heat to slag on said oor to maintainat least its surface in a fluid condition, said floor having arelatively thick. layer of ceramic material and a'metal supporting platetherefor.

4. In a furnace, a combustion chamber, a burner to burn a slag-formingfuel in said chamber, saidl chamber having a substantially horizontalslag receiving floor and side' walls held in contact with the sides ofthe floor and arranged toprevent slag leaking therebetween, .andvertical water tubes in said side walls and extending below the top .ofsaid floor, said chamber having an opening through which molten slag mayow and said burner being constructed to impart sufli cientheat to slagon said oor to maintain at least its surface in a fluid condition, saidfloor having a relatively thick layer of ceramic material and a metalsupporting plate therefor, said floor having a space beneath said plate,whereby heat therefrom may be conducted slowly away.

5,'In a furnace, means for burning a slagforming fuel, a floorconstructed to support a pool of molten slag, water cooled wallscontacting with the edges of said floor, and means permitting relativehorizontal and vertical movement between said walls and said floor, incombination with a spout coacting with a slagtap opening in one of saidwalls above the level of said oor and movable therewith upon movement ofsaid wall.

6. In a furnace, means for burning a slag-forming fuel, a floorconstructed to supporta pool .l

of molten slag, water cooled walls surrounding said floor, and resilientmeans supporting said walls independently of said floor, in combinationwith a spout associated with an opening in one of said Walls and adaptedto move therewith upon expansion or contraction of the wall.

7. In a furnace; means for burning a slag-forming fuel, water cooledwalls, and a floor having a refractory covering, said floor beingconstructed to support a pool of molten slag, in combination with meansfor sealing the joint between the water cooled walls and floor.

8. In a boiler furnace, means for burning a slag-forming fuel, watervcooled walls, and a floor constructed to support a pool of molten slag,said floor having a support independent of the walls Aand movablerelatively thereto; in combination with means forming a seal betweensaid walls and said floor, said means preventing passage of slag betweensaid floor and s'aid walls upon relative movement between said walls andsaid floor, substantially as described.

9,. In a furnace, means for burning a slag-- forming fuel; a floorconstructed to support a pool of molten slag, water cooled wallssurrounding said floor, and resilient means supporting said, wallsindependently of said floor, in combination,

with a spout associated with an -opening above the floor in one of saidwalls and adapted to move therewith upon expansion orcontraction of thewall, said walls being constructed and arranged so that slag may drainfrom said'walls to said floor.

10. In combination, a furnace, water circulating tubes inthe wallsthereof, means for burning fuelin said furnace, means for maintaining apool of molten materialwithin thefurnace, means from the molten pool tothe water circulating tubes in the walls, and means for introducing anfor applying the heat from the burning fuel and independent coolingiiuid beneath the oor of said furnace to aid in cooling the same.

11. A furnace comprising walls and a floor, water cooling means forI thewalls only, said door being constructedto support a pool of molten slag,and means for projecting a slag-forming fuel substantially horizontallyclose to the floor.

12. A furnace comprising walls and a door, water cooling means for thewalls only, said floor being constructed to support a pool of moltenslag, and a turbulent burner of high capacity arranged to project aslag-forming fuel substantially horizontally close to the floor.

13. In a furnace, a combustion chamber, a burner to burn a slag-formingfuel in said chamber, said chamber having a substantially horizontalslag receiving :door and side walls held in contact with the sides ofthe iioor and arranged toprevent slag leakage therebetween, and verticalwater tubes in said side walls extending below the top of said floor,said chamber having an opening through which molten slag may flow, andsaid burner being constructed to impart sufficient heat to slag onv saidoor to maintain at least its surface in uid condition, said floor havinga relatively thick layer of refractory material and a metalsupportingplate therefor, said floor also having space beneath saidplate whereby heat therefrom may be conducted away.

14. A boiler furnace, a floor therefor having metal supporting partsandv a solid protective layer arranged to support a pool of moltenslag,means for fluid cooling said metal oor parts, means for feedingnely-divided slag-forming fuel and air into the furnace and arranged tomaintain a pool of molten slag overlying substantially all the solidprotective layer, said furnace having a slag tap-hole, side wallsadjacent to theslag pool, all of said side walls having metal conduits,and connections for circulating cooling liquid through said metalconduits.

15. A boiler furnace, a oor therefor having metal supporting parts,blocks carried by the metal supporting parts and forming a solidprotective layer arranged to support a pool of molten slag, means forfluid cooling said metal oor parts, means for feeding4 finely-dividedslag-forming fuel and air into the furnace and arranged to maintain apool of molten slag overlying substantially all the solid protectivelayer, said furnace having a slag tap-hole, side walls adjacent to theslag pool, all of said side walls having metal conduits, and connectionsfor circulating cooling liquid through said metal conduits.-

16. A boiler furnace, a oor therefor having metal supporting parts and asolid protective layer arranged to support a pool of molten slag,

means for iluid cooling said metal oor parts, v

means for feeding nely-divided slag-forming fuel and air into thefurnace and arranged to maintain a pool of molten slag overlyingsubstantially all the solid protective layer, said furnace having a slagtap-hole, side walls adjacent to the slag pool, all of said side wallshaving metal conduits. forming spaced water tubes in said side walls andclosure means for closing the spaces between said tubes andin thermalcontact therewith, and connections for circulating cooling uid throughsaid metal conduits.

17. A boiler furnace, a oor therefor having metal supporting parts and asolid protective layer arranged to support a pool of molten slag, meansfor fluid cooling said metal floor parts, means for feedingfinely-divided slag-forming fuel and air into the furnace and arrangedto maintain a pool of molten slag overlying substantially all the solidprotective layer, said furnace having a slag taphole, side wallsadjacent to the slag pool, all of said side walls having metal conduitsforming spaced water tubes in said side walls and closure means forclosing the spaces between said tubes, said closure means havingmetallic parts in thermal contact with said tubes and refractory on saidmetallic parts, and connections for circulating cooling liquid throughsaid metal conduits.

18. A boiler furnace, a :door therefor having metal supporting parts anda solid protective layer arranged to support Aa pool of molten slag,means for fluid cooling said metal floor parts, means for feedingfinely-divided slag-forming fuel and air into the furnace and arrangedto maintain a pool of molten slag overlying substantially all the solidprotective layer, said furnace having a slag tap- -hole, side wallsadjacent to the slag pool, all of said side walls having metal conduitsforming spaced water tubes in said side walls and closure means forclosing the spaces between said tubes and in thermal contact therewith,said water tubes being arranged for less cooling in some side wall areasthan in others, and connections for circulating cooling liquid throughsaid metal conduits. I

19. In a pulverized fuel fired furnace, the combination of a combustionchamber having a bottom and side walls adjacent to a slag pool on saidbottom, all of said side walls having uid cooling tubes and a lining forsaid tubes constructed and arranged to'retain a pool of molten slagoverlying substantially all of said combustion chamber bottom, and meansfor feeding pulverized fuel and air into said chamber arrangedto-produce slag liquefying temperature in said slag pool.

20. A boiler furnace, a :door therefor having metal supporting parts anda solid protective layer arranged to. support a pool of molten slag,means for fluid cooling said metal oor parts, said furnace having a slagtap-hole, side walls adjacent to the slag pool, all of said side wallshaving metal conduits, a burner between certain of the metal conduitsand arranged to maintain a pool of molten slag overlying the solidprotective layer -of the oor, and connections for circulating coolingliquid through said metal conduits.

21. A boiler furnace, a oor therefor having metal supporting parts and asolid protective layer arranged to support a pool of molten slag, meansfor fluid cooling said metal floor parts, said furnace having a slagtap-hole, side walls adjacent to the slag pool, all of said side wallshaving metal conduits located above the furnace bottom, a burner betweencertain of the metal conduits and arranged to maintain a pool of moltenslag overlying the solid protective layer of the oor, and connectionsfor circulating cooling liquid through said metal conduits.

22. In a steam generator, a furnace having a pulverized fuel burner, abottom, side walls and an upper gas outlet, a steam generating tube bankarranged to receive heating gases from said out-` ERVIN G. BAILEY.

